Electric meter.



Patented Oct. 9, I900.

A. EDI-sou. ELECTRIUTME'TER.

(Application fled Sept. 24, 1896.)

(No Model.)

3 Sheets-Sha'at I.

Jif y No. 659,389. Patentedfict. 9, I900.

T. A. EDISON.

ELECTRIC METER. (Application filed Sept. 24, 1898.)

3 Sheets-She 2.

(No Model.)

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No. 659,389. Patented Oct. 9, 1900. T. A. smsou.

ELECTRIC METER.

(Application flled Sept. ,24, 1898.) 3 Sheets-Shaet 3.

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small but constant ratio is utilized in the determination of the total current in a con-- ATsENT OFFICE.

THOMAS A. EDISON, OF LLEWELLYN PARK, NEW JERSEY.

ELECTRIC METER.

SPECIFICATION forming pm of Letters Patent No. 659,389, dated October 9, leoo.

- I Application filed September 24, 1898. Serial No. 691,760. (No model.)

of New Jersey, have invented a certain new: and useful Improvement-inElectric Meters, (Case No. 1,000,) of which the following is a specification.

My invention relates to various new and useful improvements in'electric meters of the type wherein the electrolytic or electro-,

depositing action of the current in a shunt of sumption-circuit.

My improved meter is accurate in its;registration, it is capable of instant and easy reading, it is simple in its construction,-it is not liable to derangement,its construction is of such a character that it will. not be impaired or injured by the handling to which it may be subjected in transportation or installation, and it may be operated with a minimum current.

, or zinc amalgam, immersedin a solution of sulfate of zinc in distilled water.v Other electrodes may be employed, as will be ex plained. In order to preventevaporation of the solution and any tendency thereof to creep, and ,to thereby maintain the absolute I uniformity of the solution, I cover the solu-.

tion with a stable inorganic non-miscible liquid, such as mineraloil, of: which paraffin oil is the preferred example. Having produced an electrolytic cell of this charac-v ter whichwill be entirely unaffected by evap oration andwhich will always he possessed of a uniform rate of deposition, I connect one or two of such cells around a relatively low resistance, whereby a minute but defi; nite and constant ra'ioof current will afiect the cell or cells, and I obtain by the deposition from one electrode to the other and by positive mechanical devices an accurate reg:

istration, capable of easy reading, of the tothe movable electrodes of two cells to the two extremities of ascale-beam'supported on knifeedges or other relatively frictionless support, the electrical connections being such that while the metal is being deposited upon the movable electrode of one cell it will be stripped 0% of the movable electrode of the other celLwhereby the scale-beam will tend to move downward toward the heavier mov ableelectrode. If desired, however, a single cell may be employed, connected to one eX- tremity of the scalebeam, 2. counterweight being connected to the other extremity thereof. The beam is connected with a suitable retarding device, which opposes the stress exerted by'either of the movable electrodes of the two cells on which the deposit is taking place. In this way the scale beam, under the effect of the depositing and stripping of the metal, will partake of an extremelyslow movement in one direction or the other, the extentof such movement being constant, as I shall explain, but its relative slowness depending upon the current influencing the cells. The retarding device which I prefer to use for opposing the movements of the beam is a weight carried on an arm depend-' ing from the beam in line with the pivotthereof, which weight maybe adjustable vertically, whereby its opposing effect may be adjustedand by neans of which, also, the capacity of the .meter may be varied. The OS- cillations of the scale-beam actuate an escapement controlling a registering-train, which operates a suitable pointer or pointers of a dial or dials. The connection between the scale-beam and escapement is of a novel character, which will presently be more fully described, and is such that friction is so infinitely small as to be negligible. tering-trainis driven either bya Weightor spring, preferably the former, and since the release of the escapement takes place very infrequently, evenwhen currents ofconsiderable \olume are influencing the cell or cells, it will be possible to obtain a suflfiicient fall of the relatively lightweight as to require winding thereof only during long intervals of time. For example, in meterswhich I proximately two inches in a year, assuming ,tal current. To this end I prefer to attach The regishave constructed the fall'of the weight is ap-" the meter to be carrying its maximum load. In order that the oscillations of ,the scalebeam may be produced, the current through the cell or cells requires to be reversed at each tripping of the escapement, and I have produced an improved reversing-switch wherein only asingle movable contact is required, such reversing-switch being operated directly by the register-train and therefore imposing no stress upon the scale-beam. To prevent oxidation of the parts comprising the currentreversing devices,I plate the contact-surfaces thereof with gold or some other non-oxidizable metal.

The elements of the meter will be preferably carried on a suitable insulated board within any convenient meter-box having preferably a glass front, through which the dials maybe observed. When used in localities where low temperatures may be expected, it is desirable to employ a heating device brought into circuit by means of a thermostat if the temperature falls dangerously near the freezing-point of the liquid in the cell. Such a heating device is preferably an incandescent lamp arranged in a branch circuit across the line and in series with a thermostatic bar composed of two metals having unequal coefiicients ofexpansion. In order that changes in temperature, which necessarily affect the resistance of the cell or cells, may not result in incorrect registration, I interpose in series with the cell or cells an ordinary compensat-ingcoil, the resistance of which changes inversely with that of the cell or cells, whereby the resistance of the shunt including the cell or cells and said compensator will be always maintained constant, irrespective of changes in temperature.

In the accompanying drawings I have illustrated the preferred construction of myimproved meter; but the details thereof maybe obviously varied.

In the drawings, Figure is a front elevation of the meter with the door of the meter-case open. Fig. 2 is a side elevation and partial section of the meter. Fig. 3 is a plan view of the scale-beam and clockwork mechanism of the meter. Fig. 4 is an elevation of the clockwork mechanism. Fig. 5 is a side elevation and partial section at one end of the scale-beam. Fig. 6 is a sectional view of one of the electrolytic cells. Fig. 7 is adiagram showing the electrical connections of the meter,and Fig. 8 isa view illustrating a method of securing a continuous current for operating the meter from an alternating-current circuit.

In all of the above views corresponding parts are represented by the same numerals of reference.

1 is a case having a door 2, provided with a glass-covered opening 3, therein. The parts of the meter are carried by a board 4 or other insulating-backing within the case 1.

5 is a three-armed bracket carrying on two of its arms glass jars 6 7, each of such jars having within it a fixed electrode 8 and a movable electrode 9. These electrodes are preferably cylindrical and open-ended. The fixed electrode 8 is carried by posts 10, from which it is insulated, andby adjustment of the connections between the electrode and these posts the fixed electrode can be accurately centered with relation to the movable electrode and independent of the inclosing glass jar. The glass jars are preferably dipped exteriorly a number of times in acetate of amyl-collodion, the jar being dried after each dipping. This forms a thin tough coating on the outside of the jar, so as to preventleakage if the jar cracks. The electrodes 8 9 are made preferably of pure metallic zinc, which is amalgamated, and they are immersed in a solution 11 of a salt of the metal, in this instance sulfate of zinc. A solution of from ten to twenty-five per cent. of sulfate of zinc in distilled water gives good results. If desired, the electrodes maybe made of any other suitable metalsuch, for example, as pure silver immersed in a solution of nitrate of silver, or a solution of cyauid of silver and cyamid of potassium may be used, or the electrodes may be of pure copper immersed in a solution of sulfate of copper, or silver electrodes may be used with a solution giving chlorin by electrolysis, as a solution of hydrochloric acid, whereby instead of the metal being deposited chlorid of silver is formed on one electrode, and when the current is reversed the other electrode is coated with chlorid of silver, while the electrode first chloridized is reduced to metallic silver, no metal being deposited from the solution. The solution 11 is covered with a layer 12 of a stable inorganic non miscible liquid-such as a mineral oil, of which pure paraffin-oil is the preferred example. A thickness of one-eighth of an inch of this layer will be suificient. The presence of this layer prevents any evaporation or creeping of the solution, so that the resistance of the solution and its rate of deposition remain always constant.

The movable electrode 9 of each cell is carried by a wire 13 from a ring of ivory or other insulating material 14, hung from a stirrup 15, which in turn is hung by a knife-edge 16 from a scale-beam 17. The scale-beam is carried on knife edges 18 on standards 19. The two movable electrodes being carried by opposite ends of the scale-beam counterbalance each other.

20 is an arm depending from the scale-beam in line with knife-edges 18 and carries on its lower end an adjustable weight 21, which resists the movement of the scale-beam from its central position.

22 and 23 are plates supported by the bracket 5 and carrying a suitable registertrain 24. The shafts of the register-train carry indexes 25, which cooperate with dials 26 to register the current. The train is driven by a weight 27 or a suitably-arranged spring. The fast or escapement shaft 28 of the train carries an cscapement-arm 20, which is made as long as practicable and has at its there will be no perceptible variation in the friction even if it were measurable. The escapementshaft 28 carries a crank-pin 33, which works in a fork at the lower end of the pivoted lever 34, which lever carries at its upper end a contact-bar 35, whose contactsurface is preferably gold-plated. This contact-bar 35 is moved by the escapement' into and out of contact with springs 36 and 37. These springs approach each other at their free ends, leaving a small gap between, and

each movement of the escapement carries the contact-piece from one set of springs to the other. The ends of the springs where they make contact with the contact-piece are also preferably gold-plated. 7

An electrical connection of definite and uniform resistance is made from the base to thepivoted lever 34 by means of a flexible and non-elastic strip of metal leaf 38. The

springs 36 and 37 are mounted upon blocks of insulating material'39'and are connected with wires 40 and 41. nite and uniform electrical resistance are made with the movable electrodes by means of flexible nonelastic strips of metal foil 42 and-43, which are connected with extensions from the wires 13, which support the movable electrodes. In this way the circuits through the meter have a definite electrical resistance at all times, no circuit connection being carried through a movablejoint orbeing dependent upon surface-contact, except in the case of the reverser. Thewires 13, which support the movable electrodes, are coated, as are the glass jars 6 and 7, with a number of layers of acetateof amyl-collodion from the point of their connection withjthe movable electrodes to a. point above the surface of the liquid, so as to insulate them and prevent any electrolyticaction upon these wires or at their connections with the electrodes.

The meter, with a current-reverse! such as I have described, will be connected arounda resistance 44, made preferably of German silver. 'This resistance is connected in the circuit of one of the main conductors 45 of the circuit whose current is to be measured, such main conductor beingbroken within the meter and the resistance being located in the break. The other main conductor 46 passes directly through themeter. .The resistance 44 may heal-ranged in flat form around the point. 'rent-reverser, it is evident that the other features of my meter might be used with other Connections of defi-' inside of the case over spools 47. The two ends of the resistance are connected with the ends of the break in the main 45, while from the centerof the resistance a connection 48 is made with the resistance, which leads through a temperature-compensating spool 49 to a connection with the movable electrode of one of the cells. An incandescent lamp 50 is arranged in a branch circuit between the two main conductors, and its circuit is controlled by a thermostat 51, which closes the circuit to the lamp when the temperature approaches the freezing-point of the solution, thus preventing the freezing of the solution.

Referring to Fig. 7, in which the electrical connections are illustrated, it will be seen that the two electrolytic cells are connected in series around one half of the resistance 44 or the other half of the resistance 44, according to the position of the current-reversing contact 35, and this arrangement enables me to use a current-reverser with only one contact-point in operation at'a'ny time and which reverses the current by a simple movement from one contact-point to another contact- While I prefer to use this simple curforms of cnrrentreverser. It will be observed that when the current passes through the electrolytic cells, the scale-beam being tipped in one direction, the elevatedvmovab le electrode will have metal deposited upon it or will become heavieigwhile the depressed movable electrode will have metal stripped from it or becomes lighter. This process continues until the elevated electrode overbalances the depressed electrode sufficiently to disengage the pallet-stud 32 from the pallet 30 or 31 which is in contact with it, when the escapement will be released and the current will be reversed through the meter. of current will produce the reverse operation, and thescalebeam will move in the opposite direction. These movements are registered on the dials and correspond with uniform current Ivalues. If desired, it will be obvious that only a single cell may be employed, connected to one end of the scale-beam, the movable electrode thereof being counterbalancedby a counterweight connected to the other end of the scale-beam. -In this case the current will bereversed by the current-reverser- This reversal 7 through the single cell, the deposit first taking place upon the movable electrode of the cell to overbalance the counterweight and I prefer, however, to use two elecjupon the reversal'of the current the metal stripping'off of such movable electrode to al-. low the scale-beam to be tiltedby the counterweight.

electrolytic cells. This principle is illustrated in Fig. 8, in which 52 represents one of the main conductors of a circuit which is reduced in cross-section, so as to generate heat at the point 53, which heat is utilized to raise the temperature of the alternate junctions of a thermopile 54, from the center and ends of which are taken wires for conveying a continuous current through the meter.

I do not herein claim the use of a thermopile or equivalent-device for generating, by means of an alternating current, a small but relatively-direct current which is to be measured by an electric meter, since that invention is described and claimed in my application filed on even date herewith.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is as follows:

1. In an electric meter, the combination with a balanced scale-beam, a retarding device for resisting the oscillations of said beam, and an electrolytic cell the movable electrode of which is connected to said scale-beam, of a register-train, and an escapement operated thereby and controlled by the oscillation of said scale-beam, substantially as set forth.

2. In an electric meter, the combination with a balanced scale-beam, a weighted depending arm carried by said scale-beam for resisting the oscillations thereof, and an electrolytic cell the movable electrode of which is connected to said scale-beam, of a registertrain, and an escapement operated thereby and controlled by the oscillation of said scalebeam, substantially as set forth.

3. In an improved electric meter, the combination with a balanced scale-beam, an arm depending from said scale-beam, an adjustable weight on said arm, and an electrolytic cell the movable electrode of which is con nected to said scale-beam, of a register-train, and an escapement operated thereby and controlled by the oscillation of said scale-beam,

substantially as set forth.

4. In an electric meter, the combination with a balanced scale-beam, a retarding device for resisting the oscillations of said beam, and an electrolytic cell, the movable electrode of which is connected to said scale-beam, of a register-train, an escapement operated thereby and controlled by the oscillations of said scale-beam, and a current-reverser operated by said register-train for reversing the current through the electrolytic cell at each oscillation of the beam, substantially as set forth.

5. In an improved electric meter, the combination with a balanced scale-beam, a weighted arm depending from said beam for resisting the oscillations thereof, and an electro- -lytic cell the movable electrode of which is connected with said scale-beam, of a registertrain, an escapement operated thereby and controlled by the oscillations of said scalebeam and a current-reverser operated by said train for reversing the current through the electrolytic cell, substantially as set forth.

6. In an improved electric meter, the combination with a balanced scale -beam, a retarding device for resisting the oscillations thereof and an electrolytic cell the movable electrode of which is connected to said scalebeam, of a register-train, an escapement-arm driven by said train, two pallets carried by said arm at varying distances from the center of rotation thereof, and a pallet-stud on the scale-beam eooperatin g successively with said pallets, substantially as set forth.

7. In an improved electric meter, the combination with a balanced scale-beam, a retarding device for resisting the oscillations thereof and an electrolytic cell the movable electrode of which is connected to said scalebeam, of a register-train, a relatively-long escapement-arm driven by said train, two pallets carried by said arm at varying distances from the center of rotation thereof, and a pallet-stud on the scale-beam above the pivot thereof, and cooperating successively with said pallets, substantially as set forth.

8. In an electric meter, the combination with a scale-beam mounted on a knife-edge,

a weighted arm depending from said sealebeam vertically beneath the pivot, and an electrolytic cell the movable electrode of which is connected to said scale-beam, of a register-train, an elongated escapement-arm driven by said train, two pallets carried by the extremities of said arms at different distances from the center of rota-tion thereof, a pallet-stud on the scale-beam in line above its pivot, and a current-reverser operated by the register train for reversing the current through the electrolytic cell, substantially as set forth.

9. An electrolytic registering-meter having a scale-beam operated by electrolytic action, a power-driven escapement controlled by the scale-beam, and a current-reverser and register operated by said power-escapement, substantially as set forth.

10. In a registering electrolytic meter, the combination with a resistance, of the twopoint current-reverser operating to shunt the meter first around one half of the resistance and then around the other half, substantially as set forth.

11. In an electric meter, the combination with a balanced scale-beam, and an electrolytic cell the movable electrode of whichis connected to said scale-beam, of a registertrain, an escapement operated thereby and controlled by the oscillation of said scalebeam, the movable contact of a current-reverser operated by the register-train at each movement of the escapement, and the two stationary contacts with which the movable contact successively engages for reversing the current through said electrolytic cell, substantially as set forth.

12. In an electric meter, the combination IIO with a balanced scale-beam, and two electrolyt-ic cells the movable electrodes of which are con nected to the extremities of said scalebeam, of a register-train, an escapement 0perated thereby and controlled bythe oscillation of said scale-beam, a movable contact operated by the register-train at each movement of the escapement, two fixed contacts with each of which the said movable contact successively en gages, a divided resistance shunting both cells, and a connection between the center of such resistance and the movable contact, whereby current will be successively reversed through both cells, substantially as set forth.

13. A registering electrolytic meter having two cells whose movable electrodes are carried by the opposite ends of a scale-beam, such movable electrodes being insulated from the scale-beam and having permanent connections with the circuit through flexible metallic connections, substantially as set forth.

14. In .an improved electrolytic cell, the combination of the jar, the fixed electrode therein, and the clamping-rods for ad justably maintaining said fixed electrode in place, substantially as set forth.

15. In a registering electrolytic meter, the combination with the registering mechanism of an electrolytic device for obtaining movement of such registering mechanism, and a current-reverser for reversing the current in the electrolytic device and comprising two fixed contacts and a movable contact successively engaging such fixed contacts, the engaging surfaces of the contacts being goldplated, for the purpose substantially as described.

This specification signed and witnessed this 19th day of September, 1898.

THOMAS A. EDISON.

Witnesses:

J. F. RANDOLPH, JNo. R. TAYLOR. 

